72 lines
4.8 KiB
Markdown
72 lines
4.8 KiB
Markdown
# Calculate Level Of Detail Texture 2D node
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The Calculate Level of Detail Texture 2D node takes an input **Texture 2D** and outputs the mip level of a Texture sample. This node is useful in situations where you need to know the mip level of a Texture, such as when you might want to modify the mip level before sampling in your shader.
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The Calculate Level of Detail Texture 2D node also has a clamped and unclamped mode:
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- **Clamped**: The node clamps the returned mip level to the actual mips available on the Texture. The node uses the [CalculateLevelOfDetail](https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-calculate-lod) HLSL intrinsic function. Use this mode when you want to know which mip to sample your Texture from and restrict the result to an existing mip.
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- **Unclamped**: The node returns the ideal mip level, based on an idealized Texture with all its mips present. The node uses the [CalculateLevelOfDetailUnclamped](https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-calculate-lod-unclamped) HLSL intrinsic function. Use this mode when you need a more generic value for your mip level.
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For example, a Texture might only have 3 mips: a 64×64 mip, a 32×32 mip, and a 16×16 mip. When you use the Calculate Level Of Detail Texture 2D node in its **Clamped** mode, the node restricts the **LOD** output to one of the 3 mips on the Texture, even if the ideal mip level might be a smaller resolution, such as an 8×8 version. In its **Unclamped** mode, the node outputs the ideal 8×8 mip level, even though it doesn't exist on the Texture.
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> [!NOTE]
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> On platforms where these HLSL functions don't exist, Shader Graph determines an appropriate approximation to use, instead.
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## Create Node menu category
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The Calculate Level of Detail Texture 2D node is under the **Input** > **Texture** category in the Create Node menu.
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## Compatibility
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The Calculate Level of Detail Texture 2D [!include[nodes-compatibility-all](./snippets/nodes-compatibility-all.md)] <!-- ALL PIPELINES INCLUDE -->
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The Calculate Level of Detail Texture 2D [!include[nodes-fragment-only](./snippets/nodes-fragment-only.md)] <!-- FRAGMENT ONLY INCLUDE -->
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## Inputs
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The Calculate Level of Detail Texture 2D [!include[nodes-inputs](./snippets/nodes-inputs.md)]
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| **Name** | **Type** | **Binding** | **Description** |
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| :--- | :------ | :------ | :---------- |
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| **Texture** | Texture 2D | None | The Texture to use in the mip level calculation. |
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| **UV** | Vector 2 | UV | The UV coordinate to use to calculate the Texture's mip level. |
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| **Sampler** | SamplerState | None | The Sampler State and corresponding settings to use to calculate the Texture's mip level. |
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## Controls
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The Calculate Level of Detail Texture 2D [!include[nodes-single-control](./snippets/nodes-single-control.md)]
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| **Name** | **Type** | **Options** | **Description** |
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| :--- | :--- | :------ | :---------- |
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| **Clamp** | Toggle | True, False | When enabled, Shader Graph clamps the output mip level to the actual mips present on the provided **Texture** input. When disabled, Shader Graph returns an ideal mip level, based on an idealized Texture with all its mips present. |
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## Outputs
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The Calculate Level of Detail Texture 2D [!include[nodes-single-output](./snippets/nodes-single-output.md)] <!-- SINGLE OUTPUT PORT INCLUDE -->
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| **Name** | **Type** | **Description** |
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| :------ | :------- | :------------- |
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| **LOD** | Float | The final calculated mip level of the Texture. |
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## Example graph usage
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In the following example, a Calculate Level of Detail Texture 2D node calculates the mip level of the **Leaves_Albedo** Texture for a set of UV coordinates and a specific Sampler State. It sends the calculated mip level for the Texture to the **LOD** input port on a Sample Texture 2D LOD node, which samples the same Texture:
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## Related nodes
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<!-- OPTIONAL. Any nodes that may be related to this node in some way that's worth mentioning -->
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[!include[nodes-related](./snippets/nodes-related.md)] Calculate Level of Detail Texture 2D node:
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- [Sample Texture 2D LOD node](Sample-Texture-2D-LOD-Node.md)
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- [Sampler State node](Sampler-State-Node.md)
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- [Gather Texture 2D node](Gather-Texture-2D-Node.md)
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- [Texture 2D Asset node](Texture-2D-Asset-Node.md)
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